takes as much motion from the impelling body as it acquires itfelf. These are facts. When we call this a vis inertiæ, we only mark these facts, without pretending to have any idea of the inert power; in the fame manner as, when we talk of gravity, we mean certain effects, without comprehending that active power. It was never the meaning of Sir ISAAC NEWTON to rob fecond causes of all force or energy; though fome of his followers have endeavoured to establish that theory upon his authority. On the contrary, that great philofopher had recourse to an etherial active fluid to explain his universal attraction; though he was fo cautious and modest as to allow, that it was a mere hypothefis, not to be infifted on, without more experiments. I must confefs, that there is something in the fate of opinions a little extraordinary. DES CARTES infinuated that doctrine of the univerfal and fole efficacy of the Deity, without infifting on it. MALEBRANCHE and other CARTESIANS made it the foundation of all their philosophy. It had, however, no authority in ENGLAND. LOCKE, CLARKE, and CUDWORTH, never fo much as take notice of it, but suppose all along, that matter has a real, though fubordinate and derived power. By what means has it become so prevalent among our modern metaphyficians ?

NOTE [E], p. 91.

CCORDING to thefe explications and definitions, the idea of power is relative as much as that of caufe; and both have a reference to an effect, or fome other event conftantly conjoined with the former. When we confider the unknown circumstance of an object, by which the degree or quantity of its effect is fixed and determined, we call that its power: And accordingly, it is allowed by all philofophers, that the effect is the measure of the power. But if they had any idea of power, as it is in itself, why could not they meafare it in itself? The difpute whether the force of a body in motion be as its velocity, or the fquare of its velocity; this difpute, I say, needed not be decided by comparing its effects in equal or unequal times; but by a direct menfuration and comparison.

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As to the frequent ufe of the words, Force, Power, Energy, &c. which every where occur in common converfation, as well as in philofophy; that is no proof, that we are acquainted, in any inflance, with the connecting principle between cause and effect, or can account ultimately for the production of one thing by another. Thefe words, as commonly used, have very loofe meanings annexed to them; and their ideas are very uncertain and confused. No animal can put external bodies in motion without the fentiment of a nifus or endeavour; and every animal has a sentiment or feeling from the ftroke or blow of an external object, that is in motion. These fenfations, which are merely animal, and from which we can à priori draw no inference, we are apt to transfer to inani. mate objects, and to fuppofe, that they have fome fuch feelings, whenever they transfer or receive motion. With regard to energies, which are exerted, without our annexing to them any idea of communicated motion, we confider only the conftant experienced conjunction of the events; and as we feel a customary connexion between the ideas, we transfer that feeling to the objects; as nothing is more ufual than to apply to external bodies every internal fenfation, which they occafion.

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NOTE [F], p. 108.

HE prevalence of the doctrine of liberty may be ac. counted for, from another caufe, viz. a false fenfation or feeming experience which we have, or may have, of liberty or indifference, in many of our actions. The neceffity of any action, whether of matter or of mind, is not, properly fpeaking, a quality in the agent, but in any thinking or intelligent being, who may confider the action; and it confifts chiefly in the determination of his thoughts to infer the exiftence of that action from fome preceding objects; as liberty, when opposed to neceflity, is nothing but the want of that determination, and a certain loosenefs or indifference, which we feel, in paffing, or not paffing, from the idea of one object to that of any fucceeding one. Now we may obferve, that, though, in reflecting on human actions, we seldom feel fuch a looseness or indifference, but are commonly able to infer them with confiderable

fiderable certainty from their motives, and from the difpofitions of the agent; yet it frequently happens, that, in performing the actions themselves, we are fenfible of fomething like it: And as all refembling objects are readily taken for each other, this has been employed as a demonftrative and even intuitive proof of human liberty. We feel, that our actions are fubject to our will, on most occafions; and imagine we feel, that the will itself is fubject to nothing, because, when by a denial of it we are provoked to try, we feel, that it moves easily every way, and produces an image of itself, (or a Velleïty, as it is called in the schools) even on that fide, on which it did not fettle. This image, or faint motion, we perfuade ourselves, could, at that time, have been compleated into the thing itself; because, should that be denied, we find, upon a fecond trial, that, at present, it can. We confider not, that the fantastical defire of fhewing liberty, is here the motive of our actions. And it feems certain, that, however we may imagine we feel a liberty within ourselves, a fpectator can commonly infer our actions from our motives and character; and even where he cannot, he concludes in general, that he might, were he perfectly acquainted with every circumstance of our fituation and temper, and the moft fecret fprings of our complexion and difpofition. Now this is the very effence of neceffity, according to the foregoing doctrine.

NOTE [G], p. 110.

THUS, if a caufe be defined, that which produces any thing; it is easy to observe, that producing is fynonimous to caufing. In like manner, if a cause be defined, that by which any thing exifts; this is liable to the fame objection. For what is meant by these words, by which? Had it been faid, that a caufe is that after which any thing conftantly exifts; we should have understood the terms. For this is, indeed, all we know of the matter. And this conftancy forms the very effence of neceffity, nor have we any other idea of it.

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NOTE [H], p. 122.

INCE all reafonings concerning facts or caufes is derived merely from cuftom, it may be asked how it happens, that men fo much furpafs animals in reasoning, and one man fó much furpaffes another? Has not the fame custom the fame influence on all ?

We shall here endeavour briefly to explain the great difference in human understandings: After which the reason of the difference between men and animals will eafily be comprehended.

1. When we have lived any time, and have been accustomed to the uniformity of nature, we acquire a general habit, by which we always transfer the known to the unknown, and conceive the latter to resemble the former. By means of this general habitual principle, we regard even one experiment as the foundation of reasoning, and expect a fimilar event with fome degree of certainty, where the experiment has been made accurately, and free from all foreign circumstances. It is therefore confidered as a matter of great importance to obferve the confequences of things; and as one man may very much furpass another in attention and memory and obfervation, this will make a very great difference in their reasoning.

2. Where there is a complication of caufes to produce any effect, one mind may be much larger than another, and better able to comprehend the whole fyftem of objects, and to infer justly their confequences.

3. One man is able to carry on a chain of confequences to a greater length than another.

4. Few men can think long without running into a confufion of ideas, and mistaking one for another; and there are various degrees of this infirmity.

5. The circumftance, on which the effect depends, is frequently involved in other circumftances, which are foreign and extrinfic. The feparation of it often requires great attention, accuracy, and fubtilty.

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6. The forming of general maxims from particular obfervation is a very nice operation; and nothing is more ufual, from hafte or a narrowness of mind, which fees not on all fides, than to commit miflakes in this particular.

7. When we reason from analogies, the man, who has the greater experience or the greater promptitude of suggesting analogies, will be the better reasoner.

8. Byaffes from prejudice, education, paffion, party, &c. hang more upon one mind than another.

9. After we have acquired a confidence in human testimony, books and conversation enlarge much more the sphere of one man's experience and thought than thofe of another.

It would be easy to discover many other circumftances that make a difference in the understandings of men.

NOTE [I], p. 130.

N° O INDIAN, it is evident, could have experience that water did not freeze in cold climates. This is placing nature in a fituation quite unknown to him; and it is impoffible for him to tell à priori what will refult from it. It is making a new experiment, the confequence of which is always uncertain. One may fometimes conjecture from analogy what will follow; but ftill this is but conjecture. And it muft be confeffed, that, in the prefent cafe of freezing, the event follows contrary to the rules of analogy, and is fuch as a rational INDIAN would not look for. The operations of cold upon water are not gradual, according to the degrees of cold; but whenever it comes to the freezing point, the water paffes in a moment, from the utmoft liquidity to perfect hardness. Such an event, therefore, may be denominated extraordinary, and requires a pretty ftrong teftimony, to render it credible to people in a warm climate: But ftill it is not miraculous, nor contrary to uniform experience of the course of nature in cafes where all the circumftances are the fame. The inhabitants of SUMATRA have always feen water fluid in their own climate, and the freezing of their rivers ought to be deemed a prodigy But they never faw water in Muscovy during the winter ;

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